Enhancing the insecticidal effectiveness of AgMNPV baculovirus

ELOÍSA I. ARANA; CHRISTINA B. MCCARTHY; A.V. GOLDBERG; A. SCIOCCO-CAP; J. OLSZEWSKI; VICTOR ROMANOWSKI

Villa Carlos Paz, Córdoba, Argentina

Congreso; XXXVIII Reunión Anual de la de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2002

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

AgMNPV is a baculovirus pathogenic for a major pest of soybean. Its virions are embedded in a protective protein matrix (polyhedrin) that forms polyhedral occlusion bodies. This dsDNA virus is a valuable natural control agent, but its utility in agricultural applications has been limited by the low speed of action compared to broad range chemical insecticides. In order to circumvent this problem we set out to genetically modify the AgMNPV by inserting a gene coding for an insect-specifc neurotoxin. To this end, we developed a svstem based on the concept of homologous recombination. It includes parental viruses, engineered to express the E. coli lacZ gene and a series of transfer plasmids with viral sequences that target the recombination to the polyhedrin locus which vary in the number of genes they can bear and the promoters that drive its/their expression. A second generation of parental viruses was constructed, with lacZ gene flanked by unique restriction sites that allow the linearization of the viral DNA and significantly improved the recovery of recombinant AgMNPVs. We cotransfected insect cells with the alternative parental viruses and the different transfer vectors, containing the neurotoxin. The recombinants were plaque purified and their genomes characterized by restriction pattern. Bioassays conducted with the obtained rAgMNPVs indicated a dramatic improvement of the insecticidal capacity of AgMNPV.